An infectious disease is a clinically evident disease of humans or animals. Information collected by the World Health Organization (WHO) on global deaths shows that worldwide mortality due to infectious diseases is as high as 25.9% of all deaths, or 14.7 million deaths in 2002 (WHO World Health Report 2002). The current numbers are even higher. Influenza infections especially an influenza pandemic threats people's health and economy globally. There is a big concern on a possible influenza pandemic causing by highly pathogenic H5N1 (avian or bird) influenza virus which will cause much more deaths than the 2009 swine influenza pandemic (WHO). Currently, there are no effective medicines for the treatment of a serious condition of an influenza infection especially a serious condition after 48 hours of an influenza infection.
Vaccines are the most effective approach to prevent infectious diseases. However, vaccines are not perfect as they may cause serious adverse reactions even death. For example, the swine influenza vaccine in 1976 might be related to about 500 cases of Guillain-Barré syndrome (GBS) and 25 deaths that the vaccine had to be called off (US CDC, VAERS). The 2009 monovalent H1N1 (swine) influenza vaccine might have induced 636 serious health events, including 103 cases of GBS and 51 deaths in the United States (US CDC, VAERS). Thus far, there is no direct proof between influenza vaccines and the serious side effects. Neither, there are not any medicines for preventing and treating the serious adverse reactions of influenza vaccines or other vaccines due to the unclear pathogenic mechanisms.
Every year an estimated 2.64 million babies die at 28 weeks' gestation or more (still birth) (Flenady, V., et al. Major risk factors for stillbirth in high-income countries: a systematic review and meta-analysis. Lancet, Apr. 16, 2011; 377:1331-1340), and 4 million babies die in the first 4 weeks of life (the neonatal death)(Lawn J E, Cousens S, Zupan J. 4 million Neonatal deaths: When? Where? Why? Lancet, 2005 Mar. 5-11; 365(9462):891-900). One potential risk factor may be related to infections. Nevertheless, how an infection induces fetal or neonatal deaths is unclear.
We have developed viral free animal models by injecting various anti-pathogen antibodies into chicken embryos or pregnant mice. The results of the experiments with those animal models indicated that some of anti-pathogen antibodies induced during an infection (e.g. an influenza infection) or by a vaccine (e.g. an influenza vaccine) can be harmful and cause serious conditions such as GBS even death. Therapeutic products for preventing and treating the disorders caused by such toxic antibodies were tested using the animal models.